Quantitating terpenes/terpenoids and nicotine in plant materials and vaping products using high-temperature headspace gas chromatography–mass spectrometry

Abstract

Plants are the main source of many high-value bioactive terpenoids used in the medical, fragrance and food industries. Increasing demand for these bioactive plants and their derivative products (e.g. cannabis and extracts thereof, flavour-supplemented vaping products, etc.) requires robust approaches to verify feedstock, identify product adulteration and ensure product safety. Headspace sampling techniques in gas chromatography are frequently employed as only compounds with suitable vapour pressures are analysed. The resulting gas phase phytochemicals may better reflect those compounds that users of vaporised products are exposed to. Reported here are single-laboratory validation details for a robust testing method to quantitate select terpenes and terpenoids in dry plant materials and terpenoid-containing vaping liquids (e.g. a derivative product) using high-temperature headspace gas chromatography–mass spectrometry, with glycerol used as a headspace solvent. Validated method recoveries were 75–103%, with excellent repeatability (RSD < 5%) and intermediate precision (RSD < 12%). The use of high-temperature headspace (180 °C) permitted terpene and terpenoid profiles to be monitored at temperatures consistent with vaping conditions. In addition to terpenes/terpenoids and nicotine, cannabinoids and caffeine could potentially be included in these methods, allowing same-injection analyses of all major groups of bioactive chemicals in materials such as cannabis and related products.